almost predictable spindle bolt stripping

with almost clocklike predictability, my trimside metro 48 spindlebolt will just crossthread itself approximately every 150 hours as its being unbolted. i hand tighten the nuts till they are snug then torque them to 75 ft lbs. have you guys ever heard anything about this happening elsewhere? im getting tired of loosing it for a day + and spending ~$70 to get it rectified. Any ideas?

On the Metro fixed deck I would suspect a bent bolt or a bent shaft. It's possible that the threads are being damaged as you remvove the bolt from the shaft but I don't know how it could be cross threading on it's way out of the top nut.

im confused as to what you mean by a bent shaft? each time this happens, its my understanding the dealer has to torch the bolt off and then install a new bolt/nut. are you suggesting that its getting bent after its been installed?... which upon thinking about it doesnt make much sense since the problem area is ontop of the spindle, in the thread area. Id be tickled if we could kick this problem.

ps, can you leave me your email, i need to find a dealer on the north side.

On the Metro it can be difficult to get the nut/bolt on and off without a good impact. Most of the time if a blade bolt/nut becomes too tight it's because it wasn't tight enough when installed, the spring disc washer needs replaced or there is some form of debris between the spacers/spindle/blade etc. Granted you can do everything right and the can still self tighten. I used to run into this from time to time with my 32" metro and it always took a great deal of effort to get the bolt/nut loosened.

Generally if the blade isn't quite tight or if any of the other items listed above occurs and the blade makes an impact with something other than grass such as a rock, stick tree root etc. the blade can then self tighten making it very difficult to remove. I've even had this happen in thick tall lush grass. Rarely have I ever heard of someone needing to "torch" the bolt to remove it. It might be a good idea to take a close look at the spring disc washer. I found on my machine that this was much less a problem if I replaced them every year or so. If you find that when your remove the blade bolt the washer remains flat or doesn't have the same "cup" shape as it once did it may be a good idea to replace it.

Not all manufacturers use the "through" bolt system that we use on our fixed deck mowers, thus not all dealers are framilliar with how to address any issues with them...........including tight blade bolts.

One you get the bolt removed make sure you replace the spring disc washer and make sure your getting the blades good and tight when you install them.